src/mesa/main/depth.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2005  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 #include "glheader.h"
  27 #include "imports.h"
  28 #include "context.h"
  29 #include "depth.h"
  30 #include "enums.h"
  31 #include "hash.h"
  32 #include "macros.h"
  33 #include "mtypes.h"
  34
  35
  36 /**********************************************************************/
  37 /*****                          API Functions                     *****/
  38 /**********************************************************************/
  39
  40
  41
  42 void GLAPIENTRY
  43 _mesa_ClearDepth( GLclampd depth )
  44 {
  45    GET_CURRENT_CONTEXT(ctx);
  46    ASSERT_OUTSIDE_BEGIN_END(ctx);
  47
  48    depth = CLAMP( depth, 0.0, 1.0 );
  49
  50    if (ctx->Depth.Clear == depth)
  51       return;
  52
  53    FLUSH_VERTICES(ctx, _NEW_DEPTH);
  54    ctx->Depth.Clear = depth;
  55    if (ctx->Driver.ClearDepth)
  56       (*ctx->Driver.ClearDepth)( ctx, ctx->Depth.Clear );
  57 }
  58
  59
  60
  61 void GLAPIENTRY
  62 _mesa_DepthFunc( GLenum func )
  63 {
  64    GET_CURRENT_CONTEXT(ctx);
  65    ASSERT_OUTSIDE_BEGIN_END(ctx);
  66
  67    if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
  68       _mesa_debug(ctx, "glDepthFunc %s\n", _mesa_lookup_enum_by_nr(func));
  69
  70    switch (func) {
  71    case GL_LESS:    /* (default) pass if incoming z < stored z */
  72    case GL_GEQUAL:
  73    case GL_LEQUAL:
  74    case GL_GREATER:
  75    case GL_NOTEQUAL:
  76    case GL_EQUAL:
  77    case GL_ALWAYS:
  78    case GL_NEVER:
  79       break;
  80    default:
  81       _mesa_error( ctx, GL_INVALID_ENUM, "glDepth.Func" );
  82       return;
  83    }
  84
  85    if (ctx->Depth.Func == func)
  86       return;
  87
  88    FLUSH_VERTICES(ctx, _NEW_DEPTH);
  89    ctx->Depth.Func = func;
  90
  91    if (ctx->Driver.DepthFunc)
  92       ctx->Driver.DepthFunc( ctx, func );
  93 }
  94
  95
  96
  97 void GLAPIENTRY
  98 _mesa_DepthMask( GLboolean flag )
  99 {
 100    GET_CURRENT_CONTEXT(ctx);
 101    ASSERT_OUTSIDE_BEGIN_END(ctx);
 102
 103    if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
 104       _mesa_debug(ctx, "glDepthMask %d\n", flag);
 105
 106    /*
 107     * GL_TRUE indicates depth buffer writing is enabled (default)
 108     * GL_FALSE indicates depth buffer writing is disabled
 109     */
 110    if (ctx->Depth.Mask == flag)
 111       return;
 112
 113    FLUSH_VERTICES(ctx, _NEW_DEPTH);
 114    ctx->Depth.Mask = flag;
 115
 116    if (ctx->Driver.DepthMask)
 117       ctx->Driver.DepthMask( ctx, flag );
 118 }
 119
 120
 121
 122 /**
 123  * Specified by the GL_EXT_depth_bounds_test extension.
 124  */
 125 void GLAPIENTRY
 126 _mesa_DepthBoundsEXT( GLclampd zmin, GLclampd zmax )
 127 {
 128    GET_CURRENT_CONTEXT(ctx);
 129    ASSERT_OUTSIDE_BEGIN_END(ctx);
 130
 131    if (zmin > zmax) {
 132       _mesa_error(ctx, GL_INVALID_VALUE, "glDepthBoundsEXT(zmin > zmax)");
 133       return;
 134    }
 135
 136    zmin = CLAMP(zmin, 0.0, 1.0);
 137    zmax = CLAMP(zmax, 0.0, 1.0);
 138
 139    if (ctx->Depth.BoundsMin == zmin && ctx->Depth.BoundsMax == zmax)
 140       return;
 141
 142    FLUSH_VERTICES(ctx, _NEW_DEPTH);
 143    ctx->Depth.BoundsMin = (GLfloat) zmin;
 144    ctx->Depth.BoundsMax = (GLfloat) zmax;
 145 }
 146
 147
 148 /**********************************************************************/
 149 /*****                      Initialization                        *****/
 150 /**********************************************************************/
 151
 152
 153 /**
 154  * Initialize the depth buffer attribute group in the given context.
 155  */
 156 void _mesa_init_depth( GLcontext * ctx )
 157 {
 158    /* Depth buffer group */
 159    ctx->Depth.Test = GL_FALSE;
 160    ctx->Depth.Clear = 1.0;
 161    ctx->Depth.Func = GL_LESS;
 162    ctx->Depth.Mask = GL_TRUE;
 163
 164    /* XXX this is now per-framebuffer state */
 165 #if 00
 166    /* Z buffer stuff */
 167    if (ctx->Visual.depthBits == 0) {
 168       /* Special case.  Even if we don't have a depth buffer we need
 169        * good values for DepthMax for Z vertex transformation purposes
 170        * and for per-fragment fog computation.
 171        */
 172       ctx->DepthMax = (1 << 16) - 1;
 173       ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
 174    }
 175    else if (ctx->Visual.depthBits < 32) {
 176       ctx->DepthMax = (1 << ctx->Visual.depthBits) - 1;
 177       ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
 178    }
 179    else {
 180       /* Special case since shift values greater than or equal to the
 181        * number of bits in the left hand expression's type are undefined.
 182        */
 183       ctx->DepthMax = 0xffffffff;
 184       ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
 185    }
 186    ctx->MRD = 1.0;  /* Minimum resolvable depth value, for polygon offset */
 187 #endif
 188 }